Electronic relaxation in the S1 state of jet-cooled p-alkoxyanilines

Fluorescence lifetimes of various vibronic levels of jet-cooled p-aminophenol (AP), p-methoxyaniline (MA), p-ethoxyaniline (EA), and p-aminophenol–Ar1 complex are reported. The lifetimes were invariant for the first few hundred wavenumbers and started lowering at around 1270 cm−1 for AP, around 900 cm−1 for MA, and around 660 cm−1 for EA. Additionally, mode-specific lowering of lifetimes was observed around 850 cm−1 region for AP and MA. Fluorescence lifetimes of the vibronic levels of AP–Ar1 complex were marginally lower than those for the corresponding parent molecule excitations.